This study compared the lipid profile after three and six cycles of treatment with NuvaRing delivering 15 microg ethinylestradiol and 120 microg etonogestrel daily with a combined oral contraceptive (COC) containing ethinylestradiol 30 microg and levonorgestrel 150 microg. In the NuvaRing group 40 women were treated and 43 in the COC group. Compared with baseline, total cholesterol did not change in either group. NuvaRing did not affect HDL, but HDL, HDL2 and HDL3 levels decreased with the COC. In contrast, HDL2 increased with NuvaRing at cycle 3. LDL increased after cycles 3 and 6 with COC, and decreased after three cycles of NuvaRing treatment. Apolipoprotein A-1 levels increased with NuvaRing, but decreased with COC; apolipoprotein B and triglycerides increased, and lipoprotein(a) decreased in both groups. Sex hormone-binding globulin increased markedly more with NuvaRing, whereas corticosteroid-binding globulin levels increased less. These changes reflect the lower androgenicity of etonogestrel versus levonorgestrel and show that NuvaRing has a minimal effect on lipid profile.